An entirely different song for common encounters made again by TRG. :^)
This one's a lot nicer in that it's more original, simpler, and fits the role of a common encounter much better. Hope you enjoy!
I'm personally a believer of the "Enemy Approaching is Frisk's theme" theory, so you can expect me to feel the same about this song & Louis, even if it's not outright confirmed for canonical consistency between UT & UTTO. 

UTTO's main motif written by Ethan Harper (Not used here)
Song written by TheRadGuy
Art drawn by poody_blue, Ethan Harper, & Blaize.Mayes; animated by poody_blue

Gamejolt: gamejolt.com/games/UT_Othergrou…oody-Harper/255490
Discord: https://discord.gg/qTfFpQX

Undertale: The Otherground OST | "Rough n' Tumble Rumble", by TheRadGuy

The official Soundcloud page of Undertale: The Otherground.

Channel operated & maintained by poody_blue, the director.
Channel icon by poody_blue, Ethan Harper, and Blaize.Mayes- animated by poody_blue.
Channel banner by Cactusfries.

Uh, Hello I suppose. current header is some old cringe art.